diff --git a/AnatomyOfMatplotlib-Part4-Limits_Legends_and_Layouts.ipynb b/AnatomyOfMatplotlib-Part4-Limits_Legends_and_Layouts.ipynb
index 534fc87..633c685 100644
--- a/AnatomyOfMatplotlib-Part4-Limits_Legends_and_Layouts.ipynb
+++ b/AnatomyOfMatplotlib-Part4-Limits_Legends_and_Layouts.ipynb
@@ -3,9 +3,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "collapsed": false
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "from __future__ import print_function\n",
@@ -38,9 +36,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "collapsed": false
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "fig, (ax1, ax2) = plt.subplots(nrows=1, ncols=2, figsize=plt.figaspect(0.5))\n",
@@ -65,9 +61,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "collapsed": false
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "fig, (ax1, ax2) = plt.subplots(1, 2, figsize=plt.figaspect(0.5))\n",
@@ -108,9 +102,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "collapsed": false
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "fig, axes = plt.subplots(nrows=3)\n",
@@ -141,9 +133,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "collapsed": false
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "# Good -- setting limits after plotting is done\n",
@@ -158,9 +148,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "collapsed": false
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "# Bad -- Setting limits before plotting is done\n",
@@ -186,9 +174,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "collapsed": false
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "fig, ax = plt.subplots()\n",
@@ -213,9 +199,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "collapsed": false
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "fig, ax = plt.subplots(1, 1)\n",
@@ -241,20 +225,33 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "collapsed": false
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
-    "%load exercises/4.1-legends_and_scaling.py"
+    "# %load exercises/4.1-legends_and_scaling.py\n",
+    "import numpy as np\n",
+    "import matplotlib.pyplot as plt\n",
+    "\n",
+    "plt.style.use('classic')\n",
+    "\n",
+    "# Try to reproduce the figure shown in images/exercise_4-1.png\n",
+    "# Here's the data and colors used.\n",
+    "\n",
+    "t = np.linspace(0, 2 * np.pi, 150)\n",
+    "x1, y1 = np.cos(t), np.sin(t)\n",
+    "x2, y2 = 2 * x1, 2 * y1\n",
+    "\n",
+    "colors = ['darkred', 'darkgreen']\n",
+    "\n",
+    "# Try to plot the two circles, scale the axes as shown and add a legend\n",
+    "# Hint: it's easiest to combine `ax.axis(...)` and `ax.margins(...)` to scale\n",
+    "# the axes\n"
    ]
   },
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "collapsed": true
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "import numpy as np\n",
@@ -294,9 +291,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "collapsed": false
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "fig, ax = plt.subplots()\n",
@@ -315,9 +310,9 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "A commonly-asked question is \"How do I plot non-numerical categories?\"\n",
+    "A commonly-asked question is \"How do I plot categories?\"\n",
     "    \n",
-    "Currently, the easiest way to do this is to \"fake\" the x-values and then change the tick labels to reflect the category.\n",
+    "Starting in version 2.0, just like any other data. \n",
     "\n",
     "For example:"
    ]
@@ -325,18 +320,14 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "collapsed": false
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "data = [('apples', 2), ('oranges', 3), ('peaches', 1)]\n",
     "fruit, value = zip(*data)\n",
     "\n",
     "fig, ax = plt.subplots()\n",
-    "x = np.arange(len(fruit))\n",
-    "ax.bar(x, value, align='center', color='gray')\n",
-    "ax.set(xticks=x, xticklabels=fruit)\n",
+    "ax.bar(fruit, value, align='center', color='gray')\n",
     "plt.show()"
    ]
   },
@@ -351,9 +342,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "collapsed": false
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "fig, axes = plt.subplots(2, 2, figsize=(9, 9))\n",
@@ -377,9 +366,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "collapsed": false
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "def example_plot(ax):\n",
@@ -419,9 +406,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "collapsed": false
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "fig, (ax1, ax2) = plt.subplots(1, 2, sharex=True, sharey=True)\n",
@@ -441,9 +426,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "collapsed": false
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "fig, ax1 = plt.subplots(1, 1)\n",
@@ -466,9 +449,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "collapsed": false
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "fig, ax = plt.subplots()\n",
@@ -516,9 +497,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "collapsed": false
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "%load exercises/4.2-spines_ticks_and_subplot_spacing.py"
@@ -527,9 +506,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "collapsed": false
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "import matplotlib.pyplot as plt\n",
@@ -546,23 +523,23 @@
  ],
  "metadata": {
   "kernelspec": {
-   "display_name": "Python 2",
+   "display_name": "Python 3",
    "language": "python",
-   "name": "python2"
+   "name": "python3"
   },
   "language_info": {
    "codemirror_mode": {
     "name": "ipython",
-    "version": 2
+    "version": 3
    },
    "file_extension": ".py",
    "mimetype": "text/x-python",
    "name": "python",
    "nbconvert_exporter": "python",
-   "pygments_lexer": "ipython2",
-   "version": "2.7.12"
+   "pygments_lexer": "ipython3",
+   "version": "3.6.5"
   }
  },
  "nbformat": 4,
- "nbformat_minor": 0
+ "nbformat_minor": 1
 }